Code/HumanoidRetargeter/Core/Formats/Mmd/Bullet/BulletDynamics/WheelContactPoint.cs

A small internal class used by the physics system to represent a contact point for wheel friction resolution. It stores the two rigid bodies, world-space friction contact position and direction, maximum impulse and computes the inverse of the jacobian diagonal term used during impulse solving.

Native Interop
/*
 * C# / XNA  port of Bullet (c) 2011 Mark Neale <[email protected]>
 *
 * Bullet Continuous Collision Detection and Physics Library
 * Copyright (c) 2003-2008 Erwin Coumans  http://www.bulletphysics.com/
 *
 * This software is provided 'as-is', without any express or implied warranty.
 * In no event will the authors be held liable for any damages arising from
 * the use of this software.
 *
 * Permission is granted to anyone to use this software for any purpose,
 * including commercial applications, and to alter it and redistribute it
 * freely, subject to the following restrictions:
 *
 * 1. The origin of this software must not be misrepresented; you must not
 *    claim that you wrote the original software. If you use this software
 *    in a product, an acknowledgment in the product documentation would be
 *    appreciated but is not required.
 * 2. Altered source versions must be plainly marked as such, and must not be
 *    misrepresented as being the original software.
 * 3. This notice may not be removed or altered from any source distribution.
 */
// Adapted from BulletXNA 73b2e1b9: namespace isolation, no XNA rendering, one type per file.
#nullable disable
#pragma warning disable CS1591, CS0168, CS0219, CS0414, CS0660, CS0661, CS0659, CS0693, CS8981, CS0108, CS0114
using System;
using System.Collections.Generic;
using System.Diagnostics;
using HumanoidRetargeter.Core.Formats.Mmd.Bullet.BulletCollision;
using HumanoidRetargeter.Core.Formats.Mmd.Bullet.LinearMath;

namespace HumanoidRetargeter.Core.Formats.Mmd.Bullet.BulletDynamics;

internal class WheelContactPoint
{
	public RigidBody m_body0;
	public RigidBody m_body1;
	public IndexedVector3 m_frictionPositionWorld;
	public IndexedVector3 m_frictionDirectionWorld;
	public float m_jacDiagABInv;
	public float m_maxImpulse;
	public WheelContactPoint(RigidBody body0, RigidBody body1, ref IndexedVector3 frictionPosWorld, ref IndexedVector3 frictionDirectionWorld, float maxImpulse)
	{
		m_body0 = body0;
		m_body1 = body1;
		m_frictionPositionWorld = frictionPosWorld;
		m_frictionDirectionWorld = frictionDirectionWorld;
		m_maxImpulse = maxImpulse;
		float denom0 = body0.ComputeImpulseDenominator(ref frictionPosWorld, ref frictionDirectionWorld);
		float denom1 = body1.ComputeImpulseDenominator(ref frictionPosWorld, ref frictionDirectionWorld);
		float relaxation = 1f;
		m_jacDiagABInv = relaxation / (denom0 + denom1);
	}
}